Larynx

Question 1

What are the functions of the larynx?

Answer 1

Phonation, cough reflex, protection of the lower respiratory tract

Question 2

What is the larynx suspended by?

Answer 2

Hyoid bone

Question 3

How is the larynx covered anteriorly?

Answer 3

By infrahyoid muscles

Question 4

How is the larynx covered laterally?

Answer 4

By lobes of the thyroid gland

Question 5

What 3 sections can the internal cavity of the larynx be divided into?

Answer 5

Supraglottis - from inferior surface of epiglottis to vestibular folds

Glottis - vocal cords and 1cm below them

Subglottis - from inferior border of glottis to inferior border of the cricoid cartilage

Question 6

What is the opening between the vocal cords known as?

Answer 6

Rima glottidis

Question 7

What is the arterial supply to the larynx?

Answer 7

Superior and inferior laryngeal arteries

Question 8

What is the superior laryngeal artery derived from?

Answer 8

Branch of superior thyroid artery - derived from external carotid

Question 9

What is the inferior laryngeal artery derived from?

Answer 9

Branch of inferior thyroid artery - derived from thyrocerivcal trunk

Question 10

Which nerve does the superior laryngeal artery follow into the larynx?

Answer 10

Internal branch of the superior laryngeal nerve

Question 11

Which nerve does the inferior laryngeal artery follow into the larynx?

Answer 11

Recurrent laryngeal nerve

Question 12

Describe the sensory innervation to the larynx

Answer 12

Recurrent laryngeal nerve - infraglottis

Internal branch of the superior larngeal nerve - supraglottis

Question 13

Describe the motor innervation to the internal muscles of the larynx

Answer 13

Recurrent laryngeal nerve - all muscles except cricothyroid

External branch of the superior laryngeal nerve - cricothyroid

Question 14

What nerve is at risk during thyroid surgery?

Answer 14

Recurrent laryngeal nerve

Question 15

Which part of cartilages move the vocal cords?

Answer 15

Arytenoid cartilages

Question 16

Which is the only complete ring of cartilage?

Answer 16

Cricoid cartilage

Question 17

What is the false vocal cord?

Answer 17

Vestibular ligament

Question 18

What is the true vocal cord?

Answer 18

Vocal ligament

Question 19

What type of epithelium lines the larynx?

Answer 19

Pseudostratified ciliated columnar epithelium

Question 20

What is the gap between the 2 true vocal cords?

Answer 20

Rima glottidis

Question 21

How do you orient anterior and posterior on a laryngoscopy?

Answer 21

Point of rima glottidis is forward (anterior)

Question 22

What do the vocal cords do during inspiration and expiration?

Answer 22

Abduct (true vocal cords abduct to greater extent during deep breathing)

Question 23

What do the vocal cords do during phonation?

Answer 23

Adduct (expired air is forced through closely adducted vocal cords to vibrate a column of air)

Question 24

What happens to the vocal cords during a cough?

Answer 24

Vocal cords are powerfully adducted, intrathoracic pressure builds, then cords are suddenly abducted

Question 25

How can the pitch of vocal sounds be altered?

Answer 25

By tension and length of true vocal cords High pitch - vocal cords taut Low pitch - vocal cords relaxed

Question 26

Contraction of which muscle increases length and tension in vocal cords?

Answer 26

Cricothyroid (important for high pitch)

Question 27

What innervates cricothyroid?

Answer 27

External branch of superior laryngeal nerve

Question 28

What is seen in an injury to the superior laryngeal nerve?

Answer 28

Innervates cricothyroid | Hoarseness of voice especially when attempting high pitched sounds

Question 29

What does the larynx do during swallowing?

Answer 29

Contraction of aryepiglottic muscles acts to narrow laryngeal inlet and pull down epiglottis, assisted by elevation of larynx, closure of vocal cords

Question 30

Which nerve could become compressed as a result of an aortic arch aneurysm?

Answer 30

Left recurrent laryngeal nerve

Question 31

What position does a paralysed vocal cord assume?

Answer 31

Paramedian position - between fully abducted and fully adducted

Question 32

What symptoms could be produced as a result of a unilateral vocal cord palsy?

Answer 32

Hoarseness of voice, ineffective cough | note that contralateral side often compensates in time by crossing the midline to meet affected vocal cord

Question 33

Which vocal cord palsy is an emergency: unilateral or bilateral?

Answer 33

Bilateral | Both vocal cords in paramedian position - narrow glottis - significant airway obstruction

Question 34

How will a patient with a compromised upper airway present?

Answer 34

Stridor, raised respiratory rate, distress, hypoxia +/- cyanosis